The present invention relates to a closure system composed of a lock and several keys in which the closing of the lock, determined by magnetically controlled tumblers, can be modified in the manner that the locking code of the lock which corresponds initially to the code of the first key can be varied by the repositioning of at least one tumbler member within the lock to the code of a subsequent key, the coding being formed by individual permanent magnets which are arranged in openings in a slide and, by means of correspondingly positioned magnetization regions of a key which can be brought into a position parallel to the slide, can be lifted out to a blocking plate, whereupon the slide can be displaced into a lock-open position, a part of the permanent magnets being intended as recoding magnets.
In one known lock of the type in question, the slide receives carriers which are in toothed engagement with each other and rotatably associated with the slide, each of the carriers being provided with a recoding magnet. In this connection, provision is made so that by means of the subsequent key, the carriers having the recoding magnets can be displaced, changing the locking code. The first key is thereby cleared.